Vertex Epidural Hematoma Associated With Traumatic Arteriovenous Fistula of the Middle Meningeal Artery: A Case Report Katsumi Matsumoto, M.D., Katsuhito Akagi, M.D., Makoto Abekura, M.D., and Osamu Tasaki, M.D. Department of Neurosurgery, Hanwa Memorial Hospital, Osaka, Japan Matsumoto K, Akagi K, Abekura M, Tasaki O. Vertex epidural hematoma associates with traumatic arteriovenous fistula of the middle meningeal artery: a case report. Surg Neurol 2001;55:302– 4. BACKGROUND Vertex epidural hematomas are rare. We describe the features of a vertex epidural hematoma associated with an arteriovenous fistula (AVF) of the meningeal artery created by a laceration of the dura mater underlying a linear skull fracture. Although AVF associated with convexity epidural hematomas has been reported, we know of no such previous report of vertex epidural hematomas. CASE DESCRIPTION A 65-year-old woman presented with generalized headache following head injury. On hospital day 3, she developed a left hemiparesis. Magnetic resonance imaging (MRI) disclosed a thick epidural hematoma at the vertex. Cerebral angiography showed an AVF between the middle meningeal artery and a venous lake. On hospital day 4, the epidural hematoma was evacuated. CONCLUSION Although coronal MRI was important for diagnosis of this vertex epidural hematomas, the case particularly illustrates the importance of cerebral angiography. The delayed onset of hemiparesis most likely reflected a continuing increase in hematoma volume because of bleeding from the lacerated meningeal artery. © 2001 by Elsevier Science Inc. KEY WORDS Arteriovenous fistula, epidural hematoma, vertex. raumatic vertex epidural hematoma is a rare lesion, variously estimated to account for 1 to 8% of all extradural hematomas [2,3,6,13,18]. Clinical diagnosis is difficult because symptoms are vari- T Address reprint requests to: Dr Katsumi Matsumoto, Hanwa Memorial Hospital, 7-11-11, Karita, Sumiyoshi-ku, Osaka, 558-0011, Japan. Received August 25, 2000; accepted November 1, 2000. 0090-3019/01/$–see front matter PII S0090-3019(01)00328-7 able and nonspecific; only symptoms of intracranial hypertension such as headache and vomiting are present [1,3,4,12], while sometimes focal but anatomically confusing deficits such as paraplegia may occur [17]. Conventional axial computed tomography (CT) is unlikely to reveal the diagnosis [4,8,11, 12]. We present a patient with traumatic vertex epidural hematoma whose main symptom developed 3 days after initial injury. Cerebral angiography showed an epidural arteriovenous fistula (AVF) between a lacerated middle meningeal artery branch and a venous lake. The possible mechanisms underlying the late onset of symptoms as well as the value of cerebral angiography are discussed. Case Report CLINICAL PRESENTATION A 65-year-old woman presented with a generalized headache after she was thrown to the ground by a robber with impact to the right side of the head. She had no loss of consciousness and initially showed no neurologic abnormalities. Skull radiographs showed a linear skull fracture crossing the vertex. CT revealed an area of high density overlying both cerebral hemispheres, visible only on the highest axial slice. She was managed conservatively with observation until the third day, when right hemiparesis developed. Magnetic resonance imaging (MRI) revealed a vertex epidural hematoma with downward displacement of the sagittal sinus (Figure 1). Cerebral angiography demonstrated inward displacement of the meningeal vessels and superior sagittal sinus as well as an AVF connecting the © 2001 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010 Vertex Epidural Hematoma Surg Neurol 303 2001;55:302–4 was found just beneath the parietal fracture. Bleeding from an adjacent venous lake containing an arachnoid granulation was also seen. These bleeding points corresponded to the angiographic location of the AVF. POSTOPERATIVE COURSE The postoperative course was uneventful. Rightsided weakness improved within 1 week. The patient was discharged home with no neurologic abnormalities. Discussion Coronal T1-weighted magnetic resonance image showing the vertex epidural hematoma and downward displacement of the sagittal sinus. 1 middle meningeal artery to a venous lake adjoining the superior sagittal sinus (Figure 2). No delayed venous flow or dilated cortical veins were demonstrated. SURGICAL FINDINGS Craniotomy was performed to evacuate the epidural hematoma. After removing the hematoma, laceration of the meningeal arteries with bleeding The present case demonstrated an unusual AVF caused by laceration of the meningeal arteries and opening of a venous lake adjacent to the superior sagittal sinus. Several cases of convexity epidural hematoma in association with traumatic dural AVF were reported [5,7,9,14]. However, we are not aware of a reported angiographic finding of AVF in a case of vertex epidural hematoma. In the present case, 3 days passed between head injury and the appearance of a focal neurologic symptom. The case could be considered one of chronic epidural hematoma based on this relatively asymptomatic interval [11,15]. More than 30% of vertex epidural hematomas reportedly have such a chronic course [2]. Overall, symptom-free intervals for vertex epidural hematomas have varied from less than 1 day Left cerebral angiography. Anterior-posterior (A) and lateral (B) views showing an AVF between the middle meningeal artery and a venous lake draining into the superior sagittal sinus. Meningeal vessels were displaced inward. 2 304 Surg Neurol 2001;55:302–4 Matsumoto et al to 6 weeks [1– 4,8,10 –12,15–18]. A delayed onset of symptoms is mainly attributable to disruption of cerebral venous drainage and blockage of cerebrospinal fluid absorption [2,11,16,18]. Some cases of vertex epidural hematoma exhibit neurologic signs despite a relatively small hematoma volume, which also argues for disturbed venous drainage as a mechanism underlying evolution of symptoms [4,11]. Only Guha et al reported a case of extravasation of angiographic contrast material, suggesting another mechanism for delayed onset of symptoms in vertex epidural hematoma [4]. No delayed venous flow was seen in the present case. 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